Are the results actually good? Table 2 reports 3.40 bits/dim on CIFAR-10, but PixelRNN in 2016 got 3.06 bits/dim (Table 3 in https://arxiv.org/abs/1601.06759). I would like to compare the MNIST results also but I'm having trouble converting between bits/dim and nats in a way that gives a sensible result. It's a bit annoying that the paper does not compare to previously-reported numbers on these benchmarks.
IMO the theoretical insight w.r.t. transformers as RNNs through the kernel formulation of self-attention is more interesting than the experimental results.